Balanced slide-valve



(NoModeL) J. J. Le BEAU.

Balanced Slide Valve.

No. 234,679. atent Nov. 23,1880

n umriyl N.PE|'ERs, FHOTO-UTHOGRAPHER. WASHINGTON. D C.

' its seat.

ATENT FFICE.

JOHN J. LE BEAU, OF CINCINNATI, OHIO.

BALANCED SLIDE-VALVE.

SPECIFICATION forming part of Letters Patent No. 234,679, dated November 23, 1880.

Application filed September 20, 1880.

To all whom it may concern Be it known that 1, JOHN JACOB LE BEAU, of Cincinnati, in the county of Hamilton and State of Ohio, have invented certain new and useful Improvements inBalanced Slide-Valves, of which the following is a specification.

Myinvention isin the nature of an improvement upon that class of slide-valves which are balanced to reduce friction and wear of valve face and seat and it consists in providing a tubular or box valve, into the face of which are cored the usual cavities for the connection of the steam-ports into the cylinder with the exhaust, in combination with a peculiar device automatically operated by the steam-pressure to maintain a perfect balance of the valve on At each end of the valve and outside of the exhaust-cavities are cut or cored mortises, which connect theinteriorof the valve with the cylinder, as one or theotherof the mortises coincides with the corresponding steamport. In the center of the valve-face, or at any other convenient point, a mortise or passage is cut into the valve, which connects the interior of it with the steam-pipe by means of a corre spon ding mortise in the valve-seat. The valve has the usual rectilineal reciprocating motion, and opens and closes the steam-ports and connects the steam-ports with the exhaust-passage in the manner common to slide-valves.

In the accompanying drawings, Figure l is the vertical section of a steam chest and cylinder containing my improved Valve. Fig. 2 is a plan of the valve-seat. Fig. 3 is a plan of the valve-face, and Fig. 4 is a transverse vertical section through the valve, steam-chest, and cylinder. Fig. 5 is a detached view of the device for seating the valve.

Similar letters of reference indicate similar parts.

A is the steam-cylinder of an engine, containing the usual piston a and rod a. Bis the steam-chest, placed above or on the side of the cylinder. G is the slide-valve, cored out internally, as shown in section in Figs. 1 and 4t and by dotted lines in Fig. 3. c c are the mortises or ports in the face of the valve near the ends, which alternately communicate with the steam-ports old in the valve-seat. 0 c are cavities or pocket-s cast into the face of the valve 0 to form a passage for the ex- (No model.)

haust-steam from the ports it into the exhauststeam passage E, Fig. 1.- c is a mortise into the valve 0 to connect the interior of the steam-inlet pipe. H is a small pipe, one end of which passes through a stuffing-box, H,

into the side of the steam-pipe F, the other end of said pipe being connected to a piston or plug, H fitted to a cylindrical opening, I), in the side of the steam-chest B, to move freely therein and be steam-tight. plug H connecting the pipe H with the interior of the steam-chest, and k is a port in the plug H connecting the interior of the steamchest with the atmosphere. h is a collar on the pipe H to limit the outward movement of the plug H and pipe H, and h is a flange on the plug H to limit the inward movement of the plug and pipe.

The action of the valve is as follows: Steam flows through the pipe F and ports fand 0 into the interior of the valve 0, thence through the mortises c 0 and d d, to alternately supply the opposite ends of the cylinder A. The tubular space in the valve 0 is made much larger than the steam-pipe F, in order that no reduction of pressure shall occur in the transit of steam through the valve. The 1110- tion of the valve is precisely like that of the common slide-valve.

The pressure of steam within the valve being as great in an upward direction as it is in a downward direction, it follows that it would be raised from its seat by a force equivalent to the area of the mortises c c and 0 into the pressure of the steam within the valve if some means were not provided to balance the tendency of the valve to rise from its seat. To counteract this tendency to lift the valve from its seat I use the devices shown in Figs. 4 and 5, the area of the pipe H having the same relation to the area of the plug H as the com bined areas of the ports 0 c and a have to the area of the back of the valve 0. To illustrate the effect of this, suppose the combined area of the ports 0 c and 0 equals ten square his a port in the inches and the area of the back of the valve equals one hundred square inches, then a uniform steam-pressure on the back of the valve equal to one-tenth the steam-pressure within the valve will be sufficient to maintain it on its seat, and the frictional resistance of the valve will be represented by its weight.

The area of the steam-pipe H having the same relation to the area of the plug H that the steam-ports have to the back of the valve, it will be obvious that with a pressure in the chest less than one-tenth the pressure in the steam-pipe the plug will travel inward throughthe opening I) and uncover the port h, whence steam will flow into the chest until a pressure slightly in excess of one-tenth the pressurein the pipes F and H is acquired, when, the moment of greatest efi'ect being on the area of the plug H the plug and pipe 11 will travel outward until the port h is covered and the flow of steam into the chest ceases. Should the pressure in the pipe F and valve 0 fall until the pressure in the chest B becomes greater than one-tenth of the pressure in the valve and pipe, then, to avoid an increased friction of the valve on its seat by reason of the excess of steam-pressure in the chest, I arrange the port h which, when the plug H travels outward,-connects the steam-chest with the atmosphere, whereby the excess of pressure in the steam-chest is relieved, and the plug H travels inward to the position shown in Figs. 4 and 5, which position it occupies so long as the equilibrium of effect (pressures into areas) is maintained.

Although I have shown and prefer to use the passages c and f for the introduction of steam into the valve 0, there is another method which, in some cases, may be desired that is, by means of a pipe turned and drawfiled, screwed into the end of the valve opposite the stem G and passed through a stuflingbox in the chest B and a similar stufling-box on the steam-pipe F, which, in this arrangement, would be at the end of the steam-chest instead of the side, as shown in Figs. 2 and 4. This means, however, of connecting the steampipe with the interior of the valve is expensive to construct and maintain and very inferior to the method shown and described.

I have shown my improved valve in form known as a long slide-valve, but it is obvious thatit can be adapted with equal facility for short slide-valves by merging the two exhaust-passages into one and by placing the ports 0 and f transversely of the valve in the centers of the exhaust-cavity of the valve and the exhaust-passage in the seat.

Having described my invention, what I claim is- The combination of the tubular slide-valve G, having ports a c and c and seat 1), having corresponding ports 61 (1,6 0, and f, and steam-chest B with the plug H, having ports h and ]L2, and provided with the steam-connection H, substantially as and for the purpose described.

lntestimony whereof I have signed my name to the foregoing specification in the presence 'of two subscribing witnesses.

JOHN JACOB LE BEAU. Witnesses:

O. H. TEMPLE, EDGAR J. GRoss. 

